Methods and devices for cutting a bone containing material string into slices are well known in the art. Methods or devices for this are being used in particular for cutting pork chops, T-bone steaks or other cutting materials that include bones. A cutting tool of a cutting device can thus be configured as a sickle blade or as a blade with a spiral shaped cutting edge. Due to the sometimes rather massive bones included in the cutting material, devices of this type have to be configured very strong in the portion of the cutting device, this means in particular with respect to the cutting blade and the feed device in a portion of cutting frames disposed in front and also behind the cutting blade in order to be able to receive the rather large cutting forces occurring in particular when cutting bones and the reactive forces resulting there from.
The known devices are typically high performance machines which are operated in large meat packing operations with high cutting frequency and accordingly high volume throughput. Thus typically slices conveyed by the conveying device from the cutting device are subsequently immediately fed to a packaging device and in particular packaged in dish shaped containers with a cover configured as a clear wrapping foil. Packaging units with a plurality of slices are often sold at self service counters of large grocery stores. For esthetic reasons, this means in order to provide a particularly attractive appearance of the of the cutting material cut into slices for a customer, placement of the slices on a conveying device and also the packaging dish is typically performed in a so called scaled, this means fanned, arrangement in which the slices overlap partially. In this case the conveying is performed through a horizontally moving conveyor belt.
Alternatively also a stacked placement of the slices is possible, wherein the placement is thus performed on a placement table which is moveable in downward direction perpendicular to the feed direction in order to provide constant placement conditions for each slice. Providing a geometrically exact placement with a scaled or stacked slice arrangement has proven problematic in practical applications for material strings including bones. This is caused in particular by the fact that the meat (muscle tissue or fat) surrounding the bones physically acts totally different compared to the bone during the cutting process. Due to the hardness and brittleness of the bone, severing the bone is not a typical cutting process, but the bone is rather “chopped”. In order to better receive the cutting forces in the cutting frame and in the machine frame when severing the bone and in order to avoid unwanted shape changes of the material string during the cutting process the material string is placed onto the feed device which is typically configured as a conveyor belt, so that the bone is placed as proximal as possible to the surface of the feed device, preferably so that it is directly placed on the feed device. In this case initially the softer meat or fat portions of the material string are cut and subsequently the slice is cut off completely by cutting the bone. In this final cutting process for each slice an undesirable effect occurs due to the brittleness of the bone and the wedge shaped geometry of the portion of the cutting blade adjacent to the cutting edge, in that the slice that has just been cut off performs uncontrollable movements in feed direction. The energy required for cutting and introduced by the cutting tool rotating at high speed is namely large enough, so that the cut off slice is provided with an undesirably large impulse which accelerates it away from the blade. Thus, it is particularly disadvantageous when the directions and also the initial velocities of the “escaping” slices vary strongly and are thus not predeterminable. This leads to an uneven and geometrically imprecise placement of the scaled or stacked slices on the conveying device. In an extreme case the deviations of separation velocities and placement positions of the cut off and then 90° flipping slices can be large enough in a scaled placement, so that one slice overtakes a slice cut off previously. Due to the unevenness of the slice placement from a geometrical point of view it is, however, indispensible for the known methods that the slices are manually readjusted or inserted subsequent to placement on the conveying device or during insertion into dish shaped containers of packaging units. This is very labor intensive which in turn increases the expense of processing food strings that include bones.
An alternative generally known cutting method includes not placing the cut off slices on the conveying device in a scaled or stacked arrangement, but conveying them away in a standing arrangement. In this case there is a support device for the first slice of the packet, wherein the support device is disposed above the conveying device and moves along in feed direction. The support device prevents that the first slice flips over and the support device assures a standing conveying of the first slice on the conveyor belt, wherein the subsequently cut off slices successively form a slice packet in this manner. In this case a velocity of the conveying device corresponds to a feed velocity. Alternatively operations can only be performed without a support device in that the first slices flip over and then provide support for the slices cut off subsequently, wherein the slices are thus transported away standing upright.
The standing arrangement of a packet of cut off slices which increases in length continuously prevents that a newly cut off slice can perform an uncontrolled movement away from the blade, however, also for this known method hand finishing is required when a scaled or fanned arrangement of the slices shall be implemented instead of an optically rather unattractive stacked slice arrangement.